include/linux/i2c.h

   1 /* ------------------------------------------------------------------------- */
   2 /*                                                                           */
   3 /* i2c.h - definitions for the i2c-bus interface                             */
   4 /*                                                                           */
   5 /* ------------------------------------------------------------------------- */
   6 /*   Copyright (C) 1995-2000 Simon G. Vogl
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation; either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  21     MA 02110-1301 USA.                                                       */
  22 /* ------------------------------------------------------------------------- */
  23
  24 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and
  25    Frodo Looijaard <frodol@dds.nl> */
  26
  27 #ifndef _LINUX_I2C_H
  28 #define _LINUX_I2C_H
  29
  30 #include <linux/types.h>
  31 #ifdef __KERNEL__
  32 #include <linux/mod_devicetable.h>
  33 #include <linux/device.h>       /* for struct device */
  34 #include <linux/sched.h>        /* for completion */
  35 #include <linux/mutex.h>
  36 #include <linux/of.h>           /* for struct device_node */
  37 #include <linux/swab.h>         /* for swab16 */
  38
  39 extern struct bus_type i2c_bus_type;
  40 extern struct device_type i2c_adapter_type;
  41
  42 /* --- General options ------------------------------------------------ */
  43
  44 struct i2c_msg;
  45 struct i2c_algorithm;
  46 struct i2c_adapter;
  47 struct i2c_client;
  48 struct i2c_driver;
  49 union i2c_smbus_data;
  50 struct i2c_board_info;
  51
  52 struct module;
  53
  54 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
  55 /*
  56  * The master routines are the ones normally used to transmit data to devices
  57  * on a bus (or read from them). Apart from two basic transfer functions to
  58  * transmit one message at a time, a more complex version can be used to
  59  * transmit an arbitrary number of messages without interruption.
  60  * @count must be be less than 64k since msg.len is u16.
  61  */
  62 extern int i2c_master_send(const struct i2c_client *client, const char *buf,
  63                            int count);
  64 extern int i2c_master_recv(const struct i2c_client *client, char *buf,
  65                            int count);
  66
  67 /* Transfer num messages.
  68  */
  69 extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
  70                         int num);
  71
  72 /* This is the very generalized SMBus access routine. You probably do not
  73    want to use this, though; one of the functions below may be much easier,
  74    and probably just as fast.
  75    Note that we use i2c_adapter here, because you do not need a specific
  76    smbus adapter to call this function. */
  77 extern s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
  78                           unsigned short flags, char read_write, u8 command,
  79                           int size, union i2c_smbus_data *data);
  80
  81 /* Now follow the 'nice' access routines. These also document the calling
  82    conventions of i2c_smbus_xfer. */
  83
  84 extern s32 i2c_smbus_read_byte(const struct i2c_client *client);
  85 extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value);
  86 extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client,
  87                                     u8 command);
  88 extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client,
  89                                      u8 command, u8 value);
  90 extern s32 i2c_smbus_read_word_data(const struct i2c_client *client,
  91                                     u8 command);
  92 extern s32 i2c_smbus_write_word_data(const struct i2c_client *client,
  93                                      u8 command, u16 value);
  94
  95 static inline s32
  96 i2c_smbus_read_word_swapped(const struct i2c_client *client, u8 command)
  97 {
  98         s32 value = i2c_smbus_read_word_data(client, command);
  99
 100         return (value < 0) ? value : swab16(value);
 101 }
 102
 103 static inline s32
 104 i2c_smbus_write_word_swapped(const struct i2c_client *client,
 105                              u8 command, u16 value)
 106 {
 107         return i2c_smbus_write_word_data(client, command, swab16(value));
 108 }
 109
 110 /* Returns the number of read bytes */
 111 extern s32 i2c_smbus_read_block_data(const struct i2c_client *client,
 112                                      u8 command, u8 *values);
 113 extern s32 i2c_smbus_write_block_data(const struct i2c_client *client,
 114                                       u8 command, u8 length, const u8 *values);
 115 /* Returns the number of read bytes */
 116 extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client,
 117                                          u8 command, u8 length, u8 *values);
 118 extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
 119                                           u8 command, u8 length,
 120                                           const u8 *values);
 121 #endif /* I2C */
 122
 123 /**
 124  * struct i2c_driver - represent an I2C device driver
 125  * @class: What kind of i2c device we instantiate (for detect)
 126  * @attach_adapter: Callback for bus addition (deprecated)
 127  * @detach_adapter: Callback for bus removal (deprecated)
 128  * @probe: Callback for device binding
 129  * @remove: Callback for device unbinding
 130  * @shutdown: Callback for device shutdown
 131  * @suspend: Callback for device suspend
 132  * @resume: Callback for device resume
 133  * @alert: Alert callback, for example for the SMBus alert protocol
 134  * @command: Callback for bus-wide signaling (optional)
 135  * @driver: Device driver model driver
 136  * @id_table: List of I2C devices supported by this driver
 137  * @detect: Callback for device detection
 138  * @address_list: The I2C addresses to probe (for detect)
 139  * @clients: List of detected clients we created (for i2c-core use only)
 140  *
 141  * The driver.owner field should be set to the module owner of this driver.
 142  * The driver.name field should be set to the name of this driver.
 143  *
 144  * For automatic device detection, both @detect and @address_data must
 145  * be defined. @class should also be set, otherwise only devices forced
 146  * with module parameters will be created. The detect function must
 147  * fill at least the name field of the i2c_board_info structure it is
 148  * handed upon successful detection, and possibly also the flags field.
 149  *
 150  * If @detect is missing, the driver will still work fine for enumerated
 151  * devices. Detected devices simply won't be supported. This is expected
 152  * for the many I2C/SMBus devices which can't be detected reliably, and
 153  * the ones which can always be enumerated in practice.
 154  *
 155  * The i2c_client structure which is handed to the @detect callback is
 156  * not a real i2c_client. It is initialized just enough so that you can
 157  * call i2c_smbus_read_byte_data and friends on it. Don't do anything
 158  * else with it. In particular, calling dev_dbg and friends on it is
 159  * not allowed.
 160  */
 161 struct i2c_driver {
 162         unsigned int class;
 163
 164         /* Notifies the driver that a new bus has appeared or is about to be
 165          * removed. You should avoid using this, it will be removed in a
 166          * near future.
 167          */
 168         int (*attach_adapter)(struct i2c_adapter *) __deprecated;
 169         int (*detach_adapter)(struct i2c_adapter *) __deprecated;
 170
 171         /* Standard driver model interfaces */
 172         int (*probe)(struct i2c_client *, const struct i2c_device_id *);
 173         int (*remove)(struct i2c_client *);
 174
 175         /* driver model interfaces that don't relate to enumeration  */
 176         void (*shutdown)(struct i2c_client *);
 177         int (*suspend)(struct i2c_client *, pm_message_t mesg);
 178         int (*resume)(struct i2c_client *);
 179
 180         /* Alert callback, for example for the SMBus alert protocol.
 181          * The format and meaning of the data value depends on the protocol.
 182          * For the SMBus alert protocol, there is a single bit of data passed
 183          * as the alert response's low bit ("event flag").
 184          */
 185         void (*alert)(struct i2c_client *, unsigned int data);
 186
 187         /* a ioctl like command that can be used to perform specific functions
 188          * with the device.
 189          */
 190         int (*command)(struct i2c_client *client, unsigned int cmd, void *arg);
 191
 192         struct device_driver driver;
 193         const struct i2c_device_id *id_table;
 194
 195         /* Device detection callback for automatic device creation */
 196         int (*detect)(struct i2c_client *, struct i2c_board_info *);
 197         const unsigned short *address_list;
 198         struct list_head clients;
 199 };
 200 #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver)
 201
 202 /**
 203  * struct i2c_client - represent an I2C slave device
 204  * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address;
 205  *      I2C_CLIENT_PEC indicates it uses SMBus Packet Error Checking
 206  * @addr: Address used on the I2C bus connected to the parent adapter.
 207  * @name: Indicates the type of the device, usually a chip name that's
 208  *      generic enough to hide second-sourcing and compatible revisions.
 209  * @adapter: manages the bus segment hosting this I2C device
 210  * @driver: device's driver, hence pointer to access routines
 211  * @dev: Driver model device node for the slave.
 212  * @irq: indicates the IRQ generated by this device (if any)
 213  * @detected: member of an i2c_driver.clients list or i2c-core's
 214  *      userspace_devices list
 215  *
 216  * An i2c_client identifies a single device (i.e. chip) connected to an
 217  * i2c bus. The behaviour exposed to Linux is defined by the driver
 218  * managing the device.
 219  */
 220 struct i2c_client {
 221         unsigned short flags;           /* div., see below              */
 222         unsigned short addr;            /* chip address - NOTE: 7bit    */
 223                                         /* addresses are stored in the  */
 224                                         /* _LOWER_ 7 bits               */
 225         char name[I2C_NAME_SIZE];
 226         struct i2c_adapter *adapter;    /* the adapter we sit on        */
 227         struct i2c_driver *driver;      /* and our access routines      */
 228         struct device dev;              /* the device structure         */
 229         int irq;                        /* irq issued by device         */
 230         struct list_head detected;
 231 };
 232 #define to_i2c_client(d) container_of(d, struct i2c_client, dev)
 233
 234 extern struct i2c_client *i2c_verify_client(struct device *dev);
 235
 236 static inline struct i2c_client *kobj_to_i2c_client(struct kobject *kobj)
 237 {
 238         struct device * const dev = container_of(kobj, struct device, kobj);
 239         return to_i2c_client(dev);
 240 }
 241
 242 static inline void *i2c_get_clientdata(const struct i2c_client *dev)
 243 {
 244         return dev_get_drvdata(&dev->dev);
 245 }
 246
 247 static inline void i2c_set_clientdata(struct i2c_client *dev, void *data)
 248 {
 249         dev_set_drvdata(&dev->dev, data);
 250 }
 251
 252 /**
 253  * struct i2c_board_info - template for device creation
 254  * @type: chip type, to initialize i2c_client.name
 255  * @flags: to initialize i2c_client.flags
 256  * @addr: stored in i2c_client.addr
 257  * @platform_data: stored in i2c_client.dev.platform_data
 258  * @archdata: copied into i2c_client.dev.archdata
 259  * @of_node: pointer to OpenFirmware device node
 260  * @irq: stored in i2c_client.irq
 261  *
 262  * I2C doesn't actually support hardware probing, although controllers and
 263  * devices may be able to use I2C_SMBUS_QUICK to tell whether or not there's
 264  * a device at a given address.  Drivers commonly need more information than
 265  * that, such as chip type, configuration, associated IRQ, and so on.
 266  *
 267  * i2c_board_info is used to build tables of information listing I2C devices
 268  * that are present.  This information is used to grow the driver model tree.
 269  * For mainboards this is done statically using i2c_register_board_info();
 270  * bus numbers identify adapters that aren't yet available.  For add-on boards,
 271  * i2c_new_device() does this dynamically with the adapter already known.
 272  */
 273 struct i2c_board_info {
 274         char            type[I2C_NAME_SIZE];
 275         unsigned short  flags;
 276         unsigned short  addr;
 277         void            *platform_data;
 278         struct dev_archdata     *archdata;
 279         struct device_node *of_node;
 280         int             irq;
 281 };
 282
 283 /**
 284  * I2C_BOARD_INFO - macro used to list an i2c device and its address
 285  * @dev_type: identifies the device type
 286  * @dev_addr: the device's address on the bus.
 287  *
 288  * This macro initializes essential fields of a struct i2c_board_info,
 289  * declaring what has been provided on a particular board.  Optional
 290  * fields (such as associated irq, or device-specific platform_data)
 291  * are provided using conventional syntax.
 292  */
 293 #define I2C_BOARD_INFO(dev_type, dev_addr) \
 294         .type = dev_type, .addr = (dev_addr)
 295
 296
 297 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 298 /* Add-on boards should register/unregister their devices; e.g. a board
 299  * with integrated I2C, a config eeprom, sensors, and a codec that's
 300  * used in conjunction with the primary hardware.
 301  */
 302 extern struct i2c_client *
 303 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info);
 304
 305 /* If you don't know the exact address of an I2C device, use this variant
 306  * instead, which can probe for device presence in a list of possible
 307  * addresses. The "probe" callback function is optional. If it is provided,
 308  * it must return 1 on successful probe, 0 otherwise. If it is not provided,
 309  * a default probing method is used.
 310  */
 311 extern struct i2c_client *
 312 i2c_new_probed_device(struct i2c_adapter *adap,
 313                       struct i2c_board_info *info,
 314                       unsigned short const *addr_list,
 315                       int (*probe)(struct i2c_adapter *, unsigned short addr));
 316
 317 /* Common custom probe functions */
 318 extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr);
 319
 320 /* For devices that use several addresses, use i2c_new_dummy() to make
 321  * client handles for the extra addresses.
 322  */
 323 extern struct i2c_client *
 324 i2c_new_dummy(struct i2c_adapter *adap, u16 address);
 325
 326 extern void i2c_unregister_device(struct i2c_client *);
 327 #endif /* I2C */
 328
 329 /* Mainboard arch_initcall() code should register all its I2C devices.
 330  * This is done at arch_initcall time, before declaring any i2c adapters.
 331  * Modules for add-on boards must use other calls.
 332  */
 333 #ifdef CONFIG_I2C_BOARDINFO
 334 extern int
 335 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
 336                         unsigned n);
 337 #else
 338 static inline int
 339 i2c_register_board_info(int busnum, struct i2c_board_info const *info,
 340                         unsigned n)
 341 {
 342         return 0;
 343 }
 344 #endif /* I2C_BOARDINFO */
 345
 346 /*
 347  * The following structs are for those who like to implement new bus drivers:
 348  * i2c_algorithm is the interface to a class of hardware solutions which can
 349  * be addressed using the same bus algorithms - i.e. bit-banging or the PCF8584
 350  * to name two of the most common.
 351  */
 352 struct i2c_algorithm {
 353         /* If an adapter algorithm can't do I2C-level access, set master_xfer
 354            to NULL. If an adapter algorithm can do SMBus access, set
 355            smbus_xfer. If set to NULL, the SMBus protocol is simulated
 356            using common I2C messages */
 357         /* master_xfer should return the number of messages successfully
 358            processed, or a negative value on error */
 359         int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
 360                            int num);
 361         int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr,
 362                            unsigned short flags, char read_write,
 363                            u8 command, int size, union i2c_smbus_data *data);
 364
 365         /* To determine what the adapter supports */
 366         u32 (*functionality) (struct i2c_adapter *);
 367 };
 368
 369 /*
 370  * i2c_adapter is the structure used to identify a physical i2c bus along
 371  * with the access algorithms necessary to access it.
 372  */
 373 struct i2c_adapter {
 374         struct module *owner;
 375         unsigned int class;               /* classes to allow probing for */
 376         const struct i2c_algorithm *algo; /* the algorithm to access the bus */
 377         void *algo_data;
 378
 379         /* data fields that are valid for all devices   */
 380         struct rt_mutex bus_lock;
 381
 382         int timeout;                    /* in jiffies */
 383         int retries;
 384         struct device dev;              /* the adapter device */
 385
 386         int nr;
 387         char name[48];
 388         struct completion dev_released;
 389
 390         struct mutex userspace_clients_lock;
 391         struct list_head userspace_clients;
 392 };
 393 #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)
 394
 395 static inline void *i2c_get_adapdata(const struct i2c_adapter *dev)
 396 {
 397         return dev_get_drvdata(&dev->dev);
 398 }
 399
 400 static inline void i2c_set_adapdata(struct i2c_adapter *dev, void *data)
 401 {
 402         dev_set_drvdata(&dev->dev, data);
 403 }
 404
 405 static inline struct i2c_adapter *
 406 i2c_parent_is_i2c_adapter(const struct i2c_adapter *adapter)
 407 {
 408         struct device *parent = adapter->dev.parent;
 409
 410         if (parent != NULL && parent->type == &i2c_adapter_type)
 411                 return to_i2c_adapter(parent);
 412         else
 413                 return NULL;
 414 }
 415
 416 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *));
 417
 418 /* Adapter locking functions, exported for shared pin cases */
 419 void i2c_lock_adapter(struct i2c_adapter *);
 420 void i2c_unlock_adapter(struct i2c_adapter *);
 421
 422 /*flags for the client struct: */
 423 #define I2C_CLIENT_PEC  0x04            /* Use Packet Error Checking */
 424 #define I2C_CLIENT_TEN  0x10            /* we have a ten bit chip address */
 425                                         /* Must equal I2C_M_TEN below */
 426 #define I2C_CLIENT_WAKE 0x80            /* for board_info; true iff can wake */
 427
 428 /* i2c adapter classes (bitmask) */
 429 #define I2C_CLASS_HWMON         (1<<0)  /* lm_sensors, ... */
 430 #define I2C_CLASS_DDC           (1<<3)  /* DDC bus on graphics adapters */
 431 #define I2C_CLASS_SPD           (1<<7)  /* Memory modules */
 432
 433 /* Internal numbers to terminate lists */
 434 #define I2C_CLIENT_END          0xfffeU
 435
 436 /* Construct an I2C_CLIENT_END-terminated array of i2c addresses */
 437 #define I2C_ADDRS(addr, addrs...) \
 438         ((const unsigned short []){ addr, ## addrs, I2C_CLIENT_END })
 439
 440
 441 /* ----- functions exported by i2c.o */
 442
 443 /* administration...
 444  */
 445 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
 446 extern int i2c_add_adapter(struct i2c_adapter *);
 447 extern int i2c_del_adapter(struct i2c_adapter *);
 448 extern int i2c_add_numbered_adapter(struct i2c_adapter *);
 449
 450 extern int i2c_register_driver(struct module *, struct i2c_driver *);
 451 extern void i2c_del_driver(struct i2c_driver *);
 452
 453 /* use a define to avoid include chaining to get THIS_MODULE */
 454 #define i2c_add_driver(driver) \
 455         i2c_register_driver(THIS_MODULE, driver)
 456
 457 extern struct i2c_client *i2c_use_client(struct i2c_client *client);
 458 extern void i2c_release_client(struct i2c_client *client);
 459
 460 /* call the i2c_client->command() of all attached clients with
 461  * the given arguments */
 462 extern void i2c_clients_command(struct i2c_adapter *adap,
 463                                 unsigned int cmd, void *arg);
 464
 465 extern struct i2c_adapter *i2c_get_adapter(int nr);
 466 extern void i2c_put_adapter(struct i2c_adapter *adap);
 467
 468
 469 /* Return the functionality mask */
 470 static inline u32 i2c_get_functionality(struct i2c_adapter *adap)
 471 {
 472         return adap->algo->functionality(adap);
 473 }
 474
 475 /* Return 1 if adapter supports everything we need, 0 if not. */
 476 static inline int i2c_check_functionality(struct i2c_adapter *adap, u32 func)
 477 {
 478         return (func & i2c_get_functionality(adap)) == func;
 479 }
 480
 481 /* Return the adapter number for a specific adapter */
 482 static inline int i2c_adapter_id(struct i2c_adapter *adap)
 483 {
 484         return adap->nr;
 485 }
 486
 487 /**
 488  * module_i2c_driver() - Helper macro for registering a I2C driver
 489  * @__i2c_driver: i2c_driver struct
 490  *
 491  * Helper macro for I2C drivers which do not do anything special in module
 492  * init/exit. This eliminates a lot of boilerplate. Each module may only
 493  * use this macro once, and calling it replaces module_init() and module_exit()
 494  */
 495 #define module_i2c_driver(__i2c_driver) \
 496         module_driver(__i2c_driver, i2c_add_driver, \
 497                         i2c_del_driver)
 498
 499 #endif /* I2C */
 500 #endif /* __KERNEL__ */
 501
 502 /**
 503  * struct i2c_msg - an I2C transaction segment beginning with START
 504  * @addr: Slave address, either seven or ten bits.  When this is a ten
 505  *      bit address, I2C_M_TEN must be set in @flags and the adapter
 506  *      must support I2C_FUNC_10BIT_ADDR.
 507  * @flags: I2C_M_RD is handled by all adapters.  No other flags may be
 508  *      provided unless the adapter exported the relevant I2C_FUNC_*
 509  *      flags through i2c_check_functionality().
 510  * @len: Number of data bytes in @buf being read from or written to the
 511  *      I2C slave address.  For read transactions where I2C_M_RECV_LEN
 512  *      is set, the caller guarantees that this buffer can hold up to
 513  *      32 bytes in addition to the initial length byte sent by the
 514  *      slave (plus, if used, the SMBus PEC); and this value will be
 515  *      incremented by the number of block data bytes received.
 516  * @buf: The buffer into which data is read, or from which it's written.
 517  *
 518  * An i2c_msg is the low level representation of one segment of an I2C
 519  * transaction.  It is visible to drivers in the @i2c_transfer() procedure,
 520  * to userspace from i2c-dev, and to I2C adapter drivers through the
 521  * @i2c_adapter.@master_xfer() method.
 522  *
 523  * Except when I2C "protocol mangling" is used, all I2C adapters implement
 524  * the standard rules for I2C transactions.  Each transaction begins with a
 525  * START.  That is followed by the slave address, and a bit encoding read
 526  * versus write.  Then follow all the data bytes, possibly including a byte
 527  * with SMBus PEC.  The transfer terminates with a NAK, or when all those
 528  * bytes have been transferred and ACKed.  If this is the last message in a
 529  * group, it is followed by a STOP.  Otherwise it is followed by the next
 530  * @i2c_msg transaction segment, beginning with a (repeated) START.
 531  *
 532  * Alternatively, when the adapter supports I2C_FUNC_PROTOCOL_MANGLING then
 533  * passing certain @flags may have changed those standard protocol behaviors.
 534  * Those flags are only for use with broken/nonconforming slaves, and with
 535  * adapters which are known to support the specific mangling options they
 536  * need (one or more of IGNORE_NAK, NO_RD_ACK, NOSTART, and REV_DIR_ADDR).
 537  */
 538 struct i2c_msg {
 539         __u16 addr;     /* slave address                        */
 540         __u16 flags;
 541 #define I2C_M_TEN               0x0010  /* this is a ten bit chip address */
 542 #define I2C_M_RD                0x0001  /* read data, from slave to master */
 543 #define I2C_M_NOSTART           0x4000  /* if I2C_FUNC_PROTOCOL_MANGLING */
 544 #define I2C_M_REV_DIR_ADDR      0x2000  /* if I2C_FUNC_PROTOCOL_MANGLING */
 545 #define I2C_M_IGNORE_NAK        0x1000  /* if I2C_FUNC_PROTOCOL_MANGLING */
 546 #define I2C_M_NO_RD_ACK         0x0800  /* if I2C_FUNC_PROTOCOL_MANGLING */
 547 #define I2C_M_RECV_LEN          0x0400  /* length will be first received byte */
 548         __u16 len;              /* msg length                           */
 549         __u8 *buf;              /* pointer to msg data                  */
 550 };
 551
 552 /* To determine what functionality is present */
 553
 554 #define I2C_FUNC_I2C                    0x00000001
 555 #define I2C_FUNC_10BIT_ADDR             0x00000002
 556 #define I2C_FUNC_PROTOCOL_MANGLING      0x00000004 /* I2C_M_NOSTART etc. */
 557 #define I2C_FUNC_SMBUS_PEC              0x00000008
 558 #define I2C_FUNC_SMBUS_BLOCK_PROC_CALL  0x00008000 /* SMBus 2.0 */
 559 #define I2C_FUNC_SMBUS_QUICK            0x00010000
 560 #define I2C_FUNC_SMBUS_READ_BYTE        0x00020000
 561 #define I2C_FUNC_SMBUS_WRITE_BYTE       0x00040000
 562 #define I2C_FUNC_SMBUS_READ_BYTE_DATA   0x00080000
 563 #define I2C_FUNC_SMBUS_WRITE_BYTE_DATA  0x00100000
 564 #define I2C_FUNC_SMBUS_READ_WORD_DATA   0x00200000
 565 #define I2C_FUNC_SMBUS_WRITE_WORD_DATA  0x00400000
 566 #define I2C_FUNC_SMBUS_PROC_CALL        0x00800000
 567 #define I2C_FUNC_SMBUS_READ_BLOCK_DATA  0x01000000
 568 #define I2C_FUNC_SMBUS_WRITE_BLOCK_DATA 0x02000000
 569 #define I2C_FUNC_SMBUS_READ_I2C_BLOCK   0x04000000 /* I2C-like block xfer  */
 570 #define I2C_FUNC_SMBUS_WRITE_I2C_BLOCK  0x08000000 /* w/ 1-byte reg. addr. */
 571
 572 #define I2C_FUNC_SMBUS_BYTE             (I2C_FUNC_SMBUS_READ_BYTE | \
 573                                          I2C_FUNC_SMBUS_WRITE_BYTE)
 574 #define I2C_FUNC_SMBUS_BYTE_DATA        (I2C_FUNC_SMBUS_READ_BYTE_DATA | \
 575                                          I2C_FUNC_SMBUS_WRITE_BYTE_DATA)
 576 #define I2C_FUNC_SMBUS_WORD_DATA        (I2C_FUNC_SMBUS_READ_WORD_DATA | \
 577                                          I2C_FUNC_SMBUS_WRITE_WORD_DATA)
 578 #define I2C_FUNC_SMBUS_BLOCK_DATA       (I2C_FUNC_SMBUS_READ_BLOCK_DATA | \
 579                                          I2C_FUNC_SMBUS_WRITE_BLOCK_DATA)
 580 #define I2C_FUNC_SMBUS_I2C_BLOCK        (I2C_FUNC_SMBUS_READ_I2C_BLOCK | \
 581                                          I2C_FUNC_SMBUS_WRITE_I2C_BLOCK)
 582
 583 #define I2C_FUNC_SMBUS_EMUL             (I2C_FUNC_SMBUS_QUICK | \
 584                                          I2C_FUNC_SMBUS_BYTE | \
 585                                          I2C_FUNC_SMBUS_BYTE_DATA | \
 586                                          I2C_FUNC_SMBUS_WORD_DATA | \
 587                                          I2C_FUNC_SMBUS_PROC_CALL | \
 588                                          I2C_FUNC_SMBUS_WRITE_BLOCK_DATA | \
 589                                          I2C_FUNC_SMBUS_I2C_BLOCK | \
 590                                          I2C_FUNC_SMBUS_PEC)
 591
 592 /*
 593  * Data for SMBus Messages
 594  */
 595 #define I2C_SMBUS_BLOCK_MAX     32      /* As specified in SMBus standard */
 596 union i2c_smbus_data {
 597         __u8 byte;
 598         __u16 word;
 599         __u8 block[I2C_SMBUS_BLOCK_MAX + 2]; /* block[0] is used for length */
 600                                /* and one more for user-space compatibility */
 601 };
 602
 603 /* i2c_smbus_xfer read or write markers */
 604 #define I2C_SMBUS_READ  1
 605 #define I2C_SMBUS_WRITE 0
 606
 607 /* SMBus transaction types (size parameter in the above functions)
 608    Note: these no longer correspond to the (arbitrary) PIIX4 internal codes! */
 609 #define I2C_SMBUS_QUICK             0
 610 #define I2C_SMBUS_BYTE              1
 611 #define I2C_SMBUS_BYTE_DATA         2
 612 #define I2C_SMBUS_WORD_DATA         3
 613 #define I2C_SMBUS_PROC_CALL         4
 614 #define I2C_SMBUS_BLOCK_DATA        5
 615 #define I2C_SMBUS_I2C_BLOCK_BROKEN  6
 616 #define I2C_SMBUS_BLOCK_PROC_CALL   7           /* SMBus 2.0 */
 617 #define I2C_SMBUS_I2C_BLOCK_DATA    8
 618
 619 #endif /* _LINUX_I2C_H */